This is a follis - a silvered bronze coin, although the silver is almost worn off here - struck in the city of Nicomedia, now Izmit in Turkey, around 310-311 CE.
Maximinus - called Daia - was the nephew of the emperor Galerius, but a series of complicated political decisions and maneuvers by Licinius I, Constantine, and his uncle ultimately led to his rebellion. Licinius quickly defeated him in two set battles and had him and his family executed.
Maximinus II is a fairly easy emperor to collect, his coins are common and readily available in good grade, althoug perhaps not exactly as common as his rivals Constantine I and Licinius I. Only in bronze, though - silver and gold coins were in this period infrequently struck and this makes them rare and expensive.
Folles from Nicomedia sometimes, like in this case, feature a CMH written as a ligature after the reverse legend. We don't know why - it could be a mark of value, it could be a shortened epithet honouring the emperor.
Obverse: IMP C GAL VAL MAXIMINUS PF AVG, Laureate bust right
Reverse: GENIO AVGVSTI CMH
6.78g and 22mm
RIC VI 66c
